Kavezno izlaganje lubina (Dicentrarchus labrax) u procjeni genotoksičnog utjecaja onečišćenja

Genotoxic effects are often the earliest signs of pollution-related environmental disturbance. In this study, we used the comet assay and micronucleus test to assess DNA damage in the erythrocytes of the European sea bass (Dicentrarchus labrax) exposed to environmental pollution in situ. Fish were collected from a fi sh farm in the Trogir Bay and their cages placed at an unpolluted reference site Šolta (Nečujam Bay) and a polluted site Vranjic (Kaštela Bay) for four weeks. A group of fi sh which remained at the fi sh farm Trogir Bay were used as the second control group. Fish exposed at the Vranjic site showed a signifi cantly higher erythrocyte DNA damage, measured by the comet assay, than either control group. Micronucleus induction showed a similar gradient of DNA damage, but did not reach statistical signifi cance. Our results show that cage exposure of a marine fi sh D. labrax can be useful in environmental biomonitoring and confi rm the comet assay as a suitable tool for detecting pollution-related genotoxicity.Genotoksični učinak često je jedan od najranijih pokazatelja štetnog djelovanja onečišćenja okoliša. U ovom radu procijenjeno je oštećenje DNA u eritrocitima lubina (Dicentrarchus labrax) izloženima okolišnom onečišćenju s pomoću komet-testa i mikronukleus-testa. Lubini su prikupljeni na ribogojilištu i kavezno izloženi u periodu od četiri tjedna na dvije postaje različitog stupnja onečišćenja na jadranskoj obali: na kontrolnoj postaji Šolta (zaljev Nečujam) i na onečišćenoj postaji Vranjic (Kaštelanski zaljev). Zasebna skupina lubina skupljena na ribogojilištu poslužila je kao druga kontrola. Rezultati komet-testa pokazali su statistički značajan porast oštećenja DNA na postaji Vranjic u usporedbi s obje kontrolne postaje. Rezultati mikronukleus-testa pokazali su sličan gradijent onečišćenja, iako nisu dosegli statističku značajnost. Ovi rezultati upućuju na primjenjivost kaveznog izlaganja lubina D. labrax u biomonitoringu vodenog okoliša te potvrđuju korisnost komet-testa kao prikladne metode za detekciju genotoksičnog utjecaja onečišćenja

Bacteria and their distribution under red-tide conditions

Survey of the density of red-tide organisms and bacterioplankton as well as simultaneous determinations of temperature, salinity, pH, secchi disc and dissolved oxygen were carried out at four stations in the Kaštela Bay (middle Adriatic Sea) on a weekly basis between June 15 and September 20, 1989. A close connection between bacterioplankton and Gonyaulax polyedra was observed during the bloom manifested by high coefficients of correlation between them in the surface layers. No correlation was established in the bottom layers since vertical gradients of bacterioplankton density were considerably weaker than in phytoplankton. These differences were also shown in strong vertical gradient of pH and 02-saturation